Detection of African swine fever virus from formalin fixed and non-fixed tissues by polymerase chain reaction

Aim: Formalin fixing and paraffin embedding of tissue samples is one of the techniques for preserving the structural integrity of cells for a very long time. However, extraction and analysis of genomic material from formalin fixed tissue (FFT) remains a challenge despite numerous attempts to develop a more effective method. The success of polymerase chain reaction (PCR) depends on the quality of DNA extract. Materials and Methods: Here we assessed the conventional method of DNA extraction from FFT for African swine fever virus (ASFV) detection. The modified conventional method gave a higher quality DNA when compared with commercially available DNA extraction kits (QIAamp® DNA Mini Kit, DNeasy® Blood and Tissue Kit, and ZR Genomic DNATM Tissue MiniPrep). Results: An average A260/A280 DNA purity of 0.86-1.68 and 3.22-5.32 μg DNA/mg for formalin fixed and non-fixed tissues, respectively using a conventional method. In a reproducible and three times repeat PCR, the ASFV DNA expected product size of 278 bp was obtained from the DNA extract of the conventional method but not from the DNA extract of the commercial kits. Conclusion: The present study has demonstrated that the conventional method extracts ASFV genome better than commercial kit. In summary, the commercial kit extraction appeared not suitable to purify ASFV DNA from FFT. We, therefore, recommend that the use of the conventional method be considered for African swine fever DNA extraction from FFT. Keyword: African swine fever, detection, formalin fixed, non-formalin fixed, polymerase chain reaction.